Studies are to be conducted on the organization of Autographa californica nuclear polyhedrosis virus (AcMNPV) genes, their expression and regulation during infection. Experiments will define the organization of selected early and late genes, map the position of these genes, determine the structure of the mRNAs and sequence the flanking 5 feet sequences to identify regulatory, non-coding and coding DNA sequences of specific genes of interest. The function of certain genes will be studied by constructing deletion mutants by in vitro mutagenesis of cloned AcMNPV DNAs, and the production of mutant viruses by gene replacement. The effects of mutation will be investigated by studying the structure of the mutant gene products, stability of mutant viral transcripts and infected cell specific proteins. The purpose of these studies is to study baculovirus gene structure, organization and expression in the invertebrate eurcaryotic cell for comparison with vertebrate systems and mechanisms. And, to explore the potential for development of baculovirus DNA sequences and insect cells within the framework of new eucaryotic vector-host cloning systems.